Isothermal section at 773 K and microwave absorption properties of Pr-Fe-Ni alloys

The isothermal section at 773 K of the phase diagram of Pr-Fe-Ni system was investigated by X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive spectroscopy. The isothermal section consists of 11 single phase regions, 19 two-phase regions and 9 three-phase regions. The maximum solid solubilities of Fe in Ni, PrNi5, Pr2Ni7, PrNi3, PrNi2, Pr7Ni3 and Pr3Ni are about 80.0, 18.2, 15.4, 11.8, 1.9, 1.7 and 4.4 at%, respectively. The maximum solid solubilities of Ni in Fe and Pr2Fe17 are about 5.0 and 1.2 at%, respectively. The solid solubility of Fe in PrNi phase is negligible. The influence of Fe substitution on the microwave absorbing properties of the PrNi5 alloy was investigated. The frequency corresponding to the minimum absorption peak of Pr16.67Ni83.33-xFex (x = 0.0-17.5) shifts towards higher frequency region upon the Fe substitution. The Pr16.67Ni68.33Fe15.0 alloy exhibits the best microwave absorption properties. The minimum reflection loss of Pr16.67Ni68.33Fe15.0 powder is -35.10 dB at 9.76 GHz, and the frequency bandwidth of reflection loss smaller than -10 dB reaches about 1.60 GHz with the best matching thickness of 1.5 mm. (C) 2015 Elsevier B.V. All rights reserved.